Spraying protection area precision control method and system based on visual scanning

Abstract

The invention provides a spraying protection area precision control method and system based on visual scanning, is applied to the technical field of industrial automatic spraying and machine vision, and unifies a workpiece, an installed covering piece and a design drawing into the same physical coordinate system through three-dimensional visual scanning and coordinate mapping. Accurately calculating the deviation between the actual boundary and the design boundary of the covering part, and judging based on the deviation value: if the deviation exceeds the limit, generating a virtual correction boundary as a new reference through an algorithm; if the detection result does not exceed the limit, taking the actual boundary as a reference, generating a protection boundary inspection path based on the determined boundary reference, automatically detecting the fitting state and the self integrity of the covering part along the path, finally performing closed-loop confirmation on the detection result through a multi-dimensional condition, and outputting a protection qualified signal after all the detection results are met. Full-automatic high-precision spraying protection control from sensing deviation to dynamic adaptation to closed-loop verification is achieved, and the precision, efficiency and reliability of protection operation are greatly improved.

Description

Technical Field

[0001] This application relates to the fields of industrial automated spraying and machine vision technology, specifically to a method and system for controlling the precision of sprayed protective areas based on visual scanning. Background Technology

[0002] In the field of industrial spraying, especially in the coating process of high-precision products such as automotive parts and aerospace components, it is necessary to protect specific non-sprayed areas of the workpiece (such as threaded holes, sealing surfaces, assembly interfaces, etc.) to prevent paint contamination.

[0003] Currently, the industry's pre-coating protection workpieces mainly relies on the traditional "manual-led + semi-automated assisted" operation mode. This mode primarily depends on operators referring to CAD drawings and manually measuring and marking boundaries on the actual workpiece surface using tools such as markers and tape, or creating rigid templates that match the workpiece's shape, and then applying protective film or installing masking fixtures based on experience. This entire process has the following problems: First, the protective boundary deviation of traditional manual marking and assembly methods is generally 0.5-1mm, which is far from meeting the 0.1mm precision requirements of modern spraying. Secondly, the manual method of judging gaps cannot identify tiny gaps of 0.05mm, which can easily lead to paint seepage and contamination of non-sprayed areas during spraying. Third, the existing solutions lack accurate deviation data records, and the protection effect relies on subjective human judgment. When spraying quality problems occur, it is impossible to trace the specific source of error in the protection process. At the same time, there is no automated locking mechanism, and the masking parts are prone to loosening due to vibration during the transfer to the spraying station, which leads to protection failure and ultimately causes the workpiece to be scrapped or reworked, increasing production costs.

[0004] Therefore, a new precision control scheme for the sprayed protection area is needed. Summary of the Invention

[0005] In view of this, the embodiments of this specification provide a method and system for controlling the accuracy of the sprayed protection area based on visual scanning, which addresses the problems of low protection accuracy, poor efficiency, lack of closed-loop control and traceability in the protection of non-sprayed areas of industrial workpieces before spraying.

[0006] The embodiments in this specification provide the following technical solutions: This specification provides an embodiment of a method for controlling the accuracy of sprayed protective areas based on vision scanning, including: Obtain the design boundary data of the protected area in the workpiece to be coated; Through three-dimensional vision scanning, the actual three-dimensional spatial data of the cover installed on the surface of the workpiece and the workpiece are acquired simultaneously, and the design boundary data and the actual three-dimensional spatial data are mapped to the same physical coordinate system to establish the spatial relationship between the actual boundary and the design boundary of the workpiece and the cover. Based on the spatial correlation, the deviation between the actual boundary data and the design boundary data of the covering component is obtained; Determine whether the deviation value exceeds a first preset threshold, and determine the boundary reference data used for path generation based on the determination result; If the deviation exceeds the limit, the boundary of the covering element is corrected based on the deviation value, and the corrected boundary data is used as the boundary reference data. If it does not exceed the limit, the actual boundary data of the covering element will be used as the boundary reference data. Based on the boundary reference data, a protection boundary inspection path is generated; Based on the inspection path of the protection boundary, the adhesion state between the cover and the workpiece surface and the boundary integrity of the cover itself are detected to obtain the verification result. Based on the verification results, multi-dimensional automatic verification is performed. When all preset verification conditions are met, a verification signal indicating that the protection scheme is qualified is output.

[0007] This specification also provides an embodiment of a precision control system for sprayed protective areas based on vision scanning, the precision control system for sprayed protective areas comprising: The processing module is used to acquire the design boundary data of the area to be protected in the workpiece to be coated; The visual scanning module is used to simultaneously acquire the actual three-dimensional spatial data of the cover installed on the surface of the workpiece and the workpiece, and to map the design boundary data and the actual three-dimensional spatial data to the same physical coordinate system, thereby establishing the spatial relationship between the actual boundary and the design boundary of the workpiece and the cover. The path generation module is used to obtain the deviation value between the actual boundary data and the design boundary data of the covering component based on the spatial correlation. Determine whether the deviation value exceeds a first preset threshold, and determine the boundary reference data used for path generation based on the determination result; If the deviation exceeds the limit, the boundary of the covering element is corrected based on the deviation value, and the corrected boundary data is used as the boundary reference data. If it does not exceed the limit, the actual boundary data of the covering element will be used as the boundary reference data. Based on the boundary reference data, a protection boundary inspection path is generated; The verification module is used to detect the adhesion state between the cover and the workpiece surface and the boundary integrity of the cover itself based on the inspection path of the protection boundary, and obtain the verification result. The execution feedback module is used to perform multi-dimensional automatic verification based on the verification results. When all the verification conditions of the preset dimensions are met, a verification signal indicating that the protection scheme is qualified is output.

[0008] Compared with the prior art, the beneficial effects that at least one technical solution adopted in the embodiments of this specification can achieve include at least: This application achieves high-precision correlation and deviation quantification between the actual boundary and design boundary of the masking component through 3D visual scanning and coordinate mapping. Based on the deviation judgment results, it dynamically selects or generates optimal boundary reference data, thereby generating a precise inspection path for fitting status and integrity detection. Finally, through multi-dimensional automatic closed-loop confirmation, the accuracy of the protected boundary is stably controlled within 0.1mm without manual intervention, completely eliminating spraying contamination problems caused by human error, micro-gaps, and loose masking components. At the same time, it generates fully traceable data records, significantly improving the accuracy, efficiency, and reliability of the protection operation, and adapting to the large-scale spraying production needs of high-precision products such as automotive parts and aerospace components. Attached Figure Description To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0009] Figure 1 This is a flowchart of a method for controlling the precision of a sprayed protective area based on visual scanning, as described in this application. Figure 2 This is a data flow diagram of a vision-scan-based method for controlling the precision of a sprayed protective area, as described in this application. Figure 3 This is the deviation monitoring and compensation logic diagram in this application; Figure 4 This is the automatic confirmation and control status diagram in this application. Detailed Implementation

[0010] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0011] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0012] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0013] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. The drawings only show the components related to this application and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the shape, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0014] Additionally, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that practice can be carried out without these specific details.

[0015] Traditional workpiece protective spraying positioning and control mainly relies on a combination of "manual dominance and semi-automated equipment assistance". The specific protective operation process is usually divided into the following three stages that are highly dependent on human experience: The first step is design baseline transfer: the operator needs to manually measure the non-painted area (i.e. the protected area) marked on the workpiece's CAD design drawing using measuring tools such as tape measure and caliper, and mark the boundary on the actual workpiece surface with tools such as marker pen and tape. They may even manually cut the protective film or make a rigid shielding template according to the workpiece's shape. This process is time-consuming, usually taking 2-4 hours per piece, and the marking accuracy depends entirely on the operator's experience, resulting in poor consistency and easy introduction of human error.

[0016] The second step is the assembly of the covering parts: the protective film is pasted or the covering template is fixed to the area of ​​the workpiece to be protected by manual means. During the assembly process, the manual marking lines need to be repeatedly compared and the position of the covering parts needs to be adjusted. If there is a deviation, it needs to be manually removed and re-pasted, which not only further prolongs the operation time, but may also damage the surface of the workpiece or the covering material itself.

[0017] The third step is to confirm the protection effect: by visual inspection or simple ruler measurement, it is determined whether the masking part covers all non-sprayed areas and whether there are obvious gaps. After confirming that it is qualified, a signature is made and recorded. There is no system-level data storage and accuracy traceability, and the overall process lacks standardization and automation support.

[0018] In view of this, the inventors discovered through long-term practice and problem review that the boundary deviation between manual marking and assembly is generally on the order of 0.5-1mm, which cannot meet the ≤0.1mm requirement of modern high-precision spraying. Even experienced technicians cannot identify micro gaps of ≤0.05mm, and paint is very likely to seep in during spraying, causing contamination of non-sprayed areas. In addition, the operation effect depends on the subjective experience of the personnel, without quantitative data records. Moreover, during the workpiece flow, due to the lack of an automated locking mechanism, the cover parts are prone to displacement and loosening due to vibration and bumps, causing the protection to fail before actual spraying. Once a quality problem occurs, it is impossible to trace the specific error source in the protection link, ultimately causing the workpiece to be scrapped or reworked, increasing production costs.

[0019] Based on this, the embodiments of this specification propose a processing scheme: The overall idea is to unify the workpiece, the installed cover, and the design drawings into the same physical coordinate system through three-dimensional visual scanning and coordinate mapping, thereby accurately calculating the deviation between the actual boundary and the design boundary of the cover, and making a judgment based on the deviation value: if the deviation exceeds a preset threshold, the cover boundary is virtually corrected by an algorithm and used as a new benchmark; if it does not exceed the preset threshold, the actual boundary is directly used as the benchmark, and a protection boundary inspection path for fine detection is generated based on the determined boundary benchmark. The fit status and integrity of the cover are automatically detected along the path. Finally, the detection results are closed-loop confirmed through multi-dimensional conditions. Only when all conditions are met is a protection qualified signal output. This realizes fully automatic high-precision spraying protection control from perceiving deviation to dynamic adaptation to closed-loop verification. It ensures that the protection boundary fit error is strictly controlled within the preset threshold and avoids the displacement of the workpiece and cover in subsequent processes. Ultimately, it achieves precise protection of the area to be protected on the workpiece, taking into account both protection accuracy and operational stability, and effectively reducing the risk of workpiece damage due to protection failure.

[0020] The technical solutions provided by the various embodiments of this application are described below with reference to the accompanying drawings.

[0021] like Figure 1 As shown in the embodiments of this specification, a method for controlling the accuracy of sprayed protective areas based on visual scanning is provided, including: Step S100: Obtain the design boundary data of the area to be protected in the workpiece to be sprayed.

[0022] During implementation, the drawing file to be processed is input. The drawing file is a computer-aided design CAD format file (such as dxf or dwg format) containing workpiece design information. The shadow areas (i.e. areas to be protected) that need to be covered by spraying have been clearly marked in the drawing file by means of color filling or pattern filling.

[0023] like Figure 2 As shown, the image processing module automatically identifies and extracts the outline of the shaded area in the drawing. This image processing module can work together with edge detection algorithms (such as the Canny algorithm or the Sobel algorithm) and area filling algorithms (such as the seed filling algorithm or the scan line filling algorithm) to extract the complete boundary data of the shaded area, ensuring the original accuracy of the design datum, and converting the complete boundary data of the shaded area into coordinate information that can be used for subsequent processing.

[0024] For example, during the implementation process for a specific metal workpiece, the CAD design file (DWG format) of the metal workpiece is input. The drawing marks the shaded areas that need to be protected (the circular area around the window frame edge and the area around three bolt holes, marked by blue patterns). The image processing module is started, and the Canny edge detection algorithm (with a threshold set to 100) is used to extract the contours of the shaded areas. Combined with the seed filling algorithm (using the geometric center of each shaded area as the seed point), the complete boundary of the protected area is determined, and the extracted boundary data is converted into a coordinate set in the design coordinate system (accuracy 0.01mm). For example, the coordinates of a boundary point on the edge of the metal workpiece are marked as (152.36mm, 89.12mm, 0mm), and the coordinates of the boundary points around the bolt holes are marked as (205.48mm, 112.63mm, 0mm), and stored in the system database for later use.

[0025] Step S200: Through three-dimensional vision scanning, simultaneously acquire the actual three-dimensional spatial data of the cover installed on the surface of the workpiece and the workpiece, and map the design boundary data and the actual three-dimensional spatial data to the same physical coordinate system to establish the spatial relationship between the actual boundary and the design boundary of the workpiece and the cover.

[0026] During implementation, a laser scanner or structured light scanner is used to perform a 3D scan of the workpiece placed on the platform and the pre-installed cover components to obtain two types of core data: 3D point cloud of workpiece This includes the physical coordinates of the workpiece surface morphology, the bench positioning reference, and the key features of the workpiece. Protect the boundary data of the masking element : Segment the local point cloud of the occluding element from the overall point cloud and extract its actual boundary point coordinates. Clearly define the relative positions of the cover, the stand reference, and the workpiece features, such as "the distance between the edge of the cover and the positioning hole of the stand" or "the fit between the cover and the area to be protected on the workpiece".

[0027] Then, the coordinate system is associated to achieve the three-dimensional coordinate association between the workpiece, the cover part, and the design drawing.

[0028] Step S300: Based on the spatial correlation, obtain the deviation value between the actual boundary data and the design boundary data of the covering component.

[0029] During implementation, based on the physical form of the completed masking part and combined with the actual three-dimensional position data of the workpiece obtained in step S200, the deviation value between the boundary of the masking part and the boundary of the shaded area in the design drawing (i.e., the design boundary of the area to be protected) is calculated.

[0030] Step S400: Determine whether the deviation value exceeds a first preset threshold, and determine the boundary reference data used for path generation based on the determination result; If the deviation exceeds the limit, the boundary of the covering element is corrected based on the deviation value, and the corrected boundary data is used as the boundary reference data. If the boundary is not exceeded, the actual boundary data of the covering element will be used as the boundary reference data.

[0031] Specifically, based on the precisely calculated deviation between the boundary of the masking part and the boundary of the shaded area in the design drawing, it is determined whether there is a deviation. If the deviation exceeds the first preset threshold, it indicates that there is a large deviation between the masking part and the design drawing. In this case, it is necessary to perform virtual correction and path compensation on the boundary of the masking part so that the spraying path can closely follow the corrected boundary of the masking part.

[0032] If the deviation value does not exceed the first preset threshold, it indicates that the match between the masking part and the designed shadow area is qualified. At this time, the actual boundary of the masking part can be directly used as the reference for subsequent path generation. This step ensures high precision in the spraying operation and avoids inaccurate spraying areas or unnecessary spraying due to excessive deviation.

[0033] Step S500: Generate a protection boundary inspection path based on the boundary reference data.

[0034] In practice, the boundary of the cover that passed the verification in step S400 is used as the boundary reference. Combined with the shape of the area to be protected on the workpiece, the "protection boundary inspection path" is generated through the path generation module.

[0035] Step S600: Based on the protection boundary inspection path, the adhesion state between the cover and the workpiece surface and the boundary integrity of the cover itself are detected to obtain the verification result.

[0036] Specifically, the bench visual inspection module is activated, and it continuously moves and scans along the generated inspection path of the protection boundary to collect high-resolution images or three-dimensional point cloud data of the edge area of ​​the cover in real time.

[0037] Based on this real-time data, the system first detects whether there is a physical gap between the lower edge of the cover and the workpiece surface, and quantifies the gap width to assess the tightness of the fit. At the same time, by analyzing the contour continuity, material uniformity, and presence of damage, wrinkles, or missing parts of the cover edge, the system determines whether the physical boundary of the cover itself is complete. By combining the above detection and analysis of the fit and boundary integrity, the verification result is obtained.

[0038] Step S700: Based on the verification results, perform multi-dimensional automatic verification. When all preset verification conditions are met, output a verification signal indicating that the protection scheme is qualified.

[0039] Specifically, based on the verification results, an automatic confirmation logic containing multiple independent dimensions is automatically triggered, and different control operations are performed according to the confirmation results: if all confirmation conditions are met, a confirmation signal indicating qualification is output, such as automatically outputting a "protection scheme confirmed as passed" signal, and at the same time generating a traceable record containing verification data of each dimension, such as generating a protection confirmation report containing boundary deviation data, inspection results, and confirmation time, which is stored in the system database for quality traceability and subsequent review.

[0040] If any unmet confirmation conditions are found, the system will immediately issue an audible and visual alarm, clearly display the non-compliant items on the operation interface, and automatically lock the system, prohibiting entry into subsequent processes. After the operator corrects the issues, the partial re-inspection process from inspection and verification to confirmation can be triggered by triggering the "reconfirm" command, until the protection scheme is qualified.

[0041] If a sudden anomaly occurs during the verification process, such as a vision module failure or a power outage on the test bench, the system will automatically save the current protection data and trigger an emergency shutdown to prevent workpiece protection from failing. After the fault is cleared, the verification process can be resumed based on the saved data without having to re-execute the entire scanning and verification process, thus ensuring the continuity of operations and the integrity of the data.

[0042] This application utilizes machine vision technology to achieve high-precision coordinate association between the non-painted areas of CAD drawings and the actual workpiece and protective coverings. It accurately quantifies and compensates for deviations between the coverings and the design boundaries, generates inspection paths that fit the protective edges to verify the covering effect, and then strictly controls the protective boundary deviation to within 0.1mm through multi-dimensional automatic confirmation logic and bench locking control. This eliminates protection blind spots, gap overruns, and loosening caused by human operation errors, ultimately achieving precise protection of the non-painted areas of the workpiece, improving protection operation efficiency, ensuring the stability of spraying quality, and forming a complete protection data recording and traceability system, adapting to the large-scale spraying production needs of high-precision products such as automotive parts and aerospace components.

[0043] In some embodiments, establishing the spatial association includes: A physical coordinate system is established with the positioning features on the stand that fixes the workpiece as the origin; Map the actual three-dimensional spatial data to the physical coordinate system; The design boundary data is transformed from the drawing coordinate system to the physical coordinate system through rigid transformation.

[0044] During implementation, a physical coordinate system is established with the key positioning features of the test bench as the origin, and the 3D point cloud of the workpiece and the boundary data of the covering part are mapped to this coordinate system. Through rigid transformation (rotation matrix R + translation vector T), the boundary data of the design shadow area extracted in step one is transformed to the physical coordinate system, realizing the unification of the coordinates of "design shadow area - actual position of workpiece - boundary of covering part", as shown in the following formula: ; in, , , These are the coordinates of the boundary points of the covering component in the physical coordinate system. , The coordinates of the boundary points of the shaded area in the design coordinate system are given; R represents the rotation matrix; T represents the translation vector.

[0045] The final output consists of three sets of associated data: the overall coordinates of the workpiece in the physical coordinate system, the actual boundary coordinates of the covered part, and the mapped coordinates of the designed shadow area. These provide a direct comparison benchmark for calculating the deviation between the covered part and the designed shadow area in step three.

[0046] For example, taking the spraying process of metal workpieces with complex geometries as an example, the metal workpiece is fixed on a special stand and pre-installed with a customized protective cover. A structured light scanner (scanning resolution 0.05mm, accuracy ±0.1mm) is used to perform a 3D scan of the workpiece and the cover on the stand: on the one hand, the 3D point cloud data (Pworkpiece) of the workpiece is acquired, including the surface topography of the metal workpiece and the coordinates of the positioning holes on the stand (denoted as (0mm, 0mm, 0mm), (300mm, 0mm, 0mm)); on the other hand, the local point cloud (Pmask) of the protective cover is segmented from the overall point cloud, and the actual boundary point coordinates of the cover are extracted (such as the edge point of the metal workpiece (152.38mm, 89.11mm, 0.2mm), the edge point of the bolt hole plug (205.47mm, 112.65mm, 0.1mm)), and the relative position of the cover and the stand reference is recorded.

[0047] A physical coordinate system is established with the positioning hole of the test bench as the origin, and the boundary data of the workpiece and the cover are mapped to this coordinate system; through rigid transformation: Rotation matrix ; Translation vector ; The extracted design boundary data is converted to the physical coordinate system to achieve coordinate unification of "design protection area - actual workpiece position - cover boundary".

[0048] In some embodiments, the deviation between the actual boundary data and the design boundary data of the covering element is obtained through the following steps: Under the same physical coordinate system, the actual boundary data of the covering component is compared with the design boundary data point by point; Based on the Euclidean distance formula, the spatial distance between each point in the actual boundary data of the cover and the corresponding point in the design boundary data is calculated to obtain the deviation value of each corresponding boundary point.

[0049] During implementation, the actual boundary point cloud data of the engraved cover is collected by visual scanning equipment (such as structured light or laser scanner), and matched and compared point by point with the design shadow area boundary data extracted from CAD drawings (i.e. the design boundary data of the area to be protected) in the same physical coordinate system.

[0050] Specifically, based on the overall scanned point cloud data of the workpiece obtained in the aforementioned steps and unified to the physical coordinate system, the actual boundary data of the covering component is obtained. Then, each point in the actual boundary point set is compared point-by-point with the corresponding point in the design shadow area boundary point set, which is now in the same physical coordinate system after coordinate transformation. To accurately quantify the positional difference between the two, the Euclidean distance formula is used to evaluate the spatial distance between each corresponding boundary point. This distance is the deviation value of that point, calculated using the following formula: ; in, This represents the deviation value at the i-th point. This represents the coordinates of the actual boundary point of the i-th masking element in the physical coordinate system; Represents the coordinates of the boundary point of the shaded area in the i-th design drawing; By calculating the deviation value at each corresponding point in sequence This allows for precise quantification of the error at each boundary point, providing point-by-point quantitative basis for subsequent accuracy assessment and compensation decisions.

[0051] In some embodiments, correcting the boundary of the cover based on the deviation value includes: With the goal of minimizing the deviation value, the least squares compensation algorithm is used to fit the spatial deviation of the actual boundary data of the cover relative to the design boundary data to obtain the corrected boundary data.

[0052] In conjunction with the above embodiments, such as Figure 3 As shown, based on the calculated deviation values ​​of each boundary point, it is determined whether these deviation values ​​exceed a preset accuracy threshold. Specifically, compare the maximum value among all deviation values. Compared with the preset accuracy threshold ,if If the deviation is large, it indicates that there is a significant discrepancy between the masking part and the design drawing. At this point, the compensation mechanism is activated, and the least squares compensation algorithm is used to generate path correction, adjust the coordinate parameters of the subsequent spraying path, and eliminate the deviation between the masking part and the design shadow area.

[0053] The core objective of the least squares compensation algorithm is to minimize the deviation between the actual boundary point and the design boundary point. By optimizing the calculation, the corrected path coordinates are obtained, and the path is adjusted so that the spraying path can closely follow the corrected virtual masking boundary, ensuring a high-precision match between the masking position and the target area.

[0054] For example: a corresponding point on the edge of a metal workpiece (a point of the covering part in the physical coordinate system). Design points ), then, the deviation value Calculations showed that the maximum deviation at all boundary points was 0.08 mm, which did not exceed the preset accuracy threshold (0.1 mm). However, during the fit inspection, a 0.06 mm gap was found between the bolt hole plug and the workpiece surface, exceeding the allowable gap threshold of 0.05 mm. In this case, the system used a least squares compensation algorithm to generate a local correction amount (such as Z-axis translation) for this area. The machine then drives the bench fine-tuning mechanism to adjust the position of the plug. After adjustment, it is re-tested and the gap at that point is reduced to 0.04mm, meeting the set accuracy and fit requirements. Thus, without making extensive changes to the masking parts, the protection effect is optimized through local path compensation, providing a core position reference guarantee for subsequent precise spraying.

[0055] In some embodiments, the protection boundary inspection path meets the following requirements: Completely covers the contact boundary between the cover and the workpiece surface; When there are multiple masking elements, the splicing boundaries between all masking elements must also be completely covered; The spacing between adjacent path points in the protection boundary inspection path is set according to a preset protection accuracy threshold.

[0056] Specifically, the qualified boundary of the cover (i.e., the determined boundary reference data) is used as the geometric reference for path generation. Combined with the topography of the area to be protected on the workpiece, the path generation module generates a "protection boundary inspection path". The generation of this path must meet the following requirements: The path must completely cover all boundaries to be inspected, including: all the contact boundaries between the cover and the workpiece surface, and the splicing boundaries between the cover when there are multiple cover components, to ensure that there are no blind spots in the inspection of the entire protected area.

[0057] To ensure that the spatial resolution of the inspection data is sufficient to identify minute defects, the spacing between adjacent sampling points on the path is set according to the set protection accuracy threshold. For example, when the protection accuracy threshold is set to 0.1mm, the spacing between path points can be set to 0.05mm.

[0058] For example, in an implementation process targeting a certain metal workpiece, the path point spacing was set to 0.05mm. This path completely covered the entire bonding boundary between the metal workpiece and the cover (approximately 1200mm in length), and simultaneously covered the edges of three bolt hole plugs (each with a circumference of approximately 50mm). There were no blind spots in the inspection, achieving continuous, high-resolution coverage of the entire boundary of the area to be protected without any omissions, thus laying a reliable path foundation for subsequent high-precision visual inspection.

[0059] In some embodiments, after generating the protection boundary inspection path, the protection boundary inspection path is subjected to noise reduction processing, including: Based on the coordinates of the path points, the tangent angles of adjacent path points are obtained; The positions of the path points are adjusted according to the changes in the tangent angle to eliminate abrupt changes or intersections in the path.

[0060] During implementation, to improve the smoothness of the inspection path and the reliability of the detection, the generated path is denoised to remove path fluctuations caused by scanning noise. Specifically, based on the path point sequence, the tangent angle between adjacent path points is calculated using the atan2 function. The formula is as follows: ; in, and Given the coordinates of adjacent path points, calculate the tangent angle between adjacent path points. It identifies and adjusts sections with abrupt changes or drastic fluctuations in direction angle, thereby eliminating sharp turns and intersections in the path, ensuring that the path is free of abrupt changes and intersections, and is compatible with the movement characteristics of the benchtop vision inspection module.

[0061] For example, in an implementation process targeting a certain metal workpiece, the coordinates of two adjacent points in the path are respectively and Then the tangent angle for: ; The results show that the direction of this path changes gradually without abrupt changes. At the same time, by optimizing the overall path through topology analysis and dynamic programming, redundant detours and self-intersecting structures are eliminated while ensuring coverage of all inspection boundaries. Ultimately, the total length of the entire inspection path is controlled at 1350mm, achieving both full coverage and ensuring movement efficiency and stability.

[0062] In some embodiments, detecting the adhesion state between the cover and the workpiece surface and the boundary integrity of the cover itself includes: The visual sensor moves along the inspection path of the protection boundary to collect image data or three-dimensional point cloud data of the interface area between the cover and the workpiece surface in real time. Based on the image or 3D point cloud data, the gap value between the actual boundary of the masking component and the workpiece surface is obtained; Determine whether the gap value at the verification location exceeds a preset bonding tolerance threshold. If it does, the verification location is identified as a bonding defect point, and the location information is recorded. Based on the image or 3D point cloud data, the real-time boundary data of the masking component at the current verification position is obtained; The real-time boundary data is compared with the boundary reference data to determine whether the boundary of the verification position is damaged, missing, warped, or the local offset exceeds the preset contour offset threshold. If so, the verification position is determined as an integrity defect point and the position information is recorded.

[0063] In conjunction with the above embodiments, the benchtop vision inspection module (a robotic arm equipped with a 5-megapixel industrial camera) is activated, and it moves continuously and stably along the generated inspection path of the protection boundary. During the movement, images or 3D point cloud data of the area covered by the path are collected in real time, and the following two types of core verifications are performed: Fit verification: Based on real-time data acquisition, the fit between the cover and the workpiece surface is judged by visual recognition. If there is a gap and the gap width exceeds the set allowable threshold, such as gap > 0.05mm, the position is marked as a "protection hazard point" and the position coordinates are output. Boundary integrity verification: The actual boundary of the cover obtained in real time during the inspection is compared with the boundary of the qualified cover (i.e. the determined boundary reference data). If the current boundary is found to have local missing parts (such as broken, missing, or warped edges of the cover), or if the deviation of the actual boundary of a local area from the qualified reference boundary exceeds the preset contour offset threshold (e.g., >0.08mm), a secondary correction prompt is triggered. The prompt may include the specific problem type, location coordinates, and suggested adjustment direction.

[0064] In some embodiments, a verification report is generated based on the detection results; If no fitting defects or integrity defects are detected, a protection boundary verification report will be generated. If at least one defect is detected, a protection boundary verification anomaly report is generated; The protection boundary verification anomaly report includes at least: defect location information and correction suggestions.

[0065] Based on the above embodiments, after completing the fit verification and boundary integrity verification along the inspection path, the system generates a corresponding report according to the verification results: If no potential hazards are found in any of the inspected areas, a "Protection Boundary Verification Passed" report will be output. This report may include information such as the coverage area of ​​the inspection path and the conclusions of each test item.

[0066] If potential hazards are found, a report containing a detailed description of the problem will be generated, listing the location of the hazard and suggestions for correction.

[0067] For example, during an implementation targeting the window frame and bolt hole area of ​​a metal workpiece, the bench vision inspection module was activated and moved along the inspection path to complete real-time detection: the fit verification showed that there were no gaps exceeding the standard in the window frame protective film, and the bolt hole plugs were well fitted; the boundary integrity verification compared the inspected boundary with the qualified boundary, and the deviation values ​​were all ≤0.08mm, with no damage or offset. Based on all the above verification results, the final output was a qualified protection boundary verification report.

[0068] In some embodiments, such as Figure 4 As shown, the confirmation conditions for the preset dimension include: Boundary accuracy conditions: Based on the verification results, it is confirmed that the deviation values ​​between the boundary reference data and the design boundary do not exceed the first preset threshold, and there are no unresolved protection vulnerabilities. The bench positioning conditions are as follows: the positioning looseness of the workpiece and the cover on the bench is less than the second preset threshold, and the repeatability error of the bench itself is less than the third preset threshold. The visual matching condition is based on an image similarity algorithm to obtain the similarity between the real-time image of the area to be protected on the workpiece and the corresponding area image in the design drawing, and to confirm that the similarity is not lower than a preset matching threshold.

[0069] Specifically, the confirmation logic is automatically triggered based on the protection boundary verification results. Only when three core conditions are met simultaneously can the protection scheme be deemed qualified: First, the boundary accuracy condition requires that the deviation value of all points on the protected boundary does not exceed the preset accuracy threshold, and there are no uncorrected fitting gaps, boundary damage or other potential problems. Secondly, the positioning conditions of the test bench are required. The workpiece and the cover are checked for looseness by using photoelectric switches, displacement sensors and other equipment mounted on the test bench (the looseness is usually required to be less than 0.03mm). At the same time, the repeatability error of the test bench itself must be controlled within the allowable range (e.g. ≤0.02mm) to ensure the overall positioning stability. Finally, there is the visual recognition condition. The bench vision module is used to capture images of the area of ​​the workpiece to be protected. The image similarity algorithm, such as the Structural Similarity Index (SSIM), is used to calculate the matching degree between the captured image and the corresponding shaded area in the design drawing. The matching degree must reach a preset high standard (e.g., 99.5% or above) to confirm the overall coverage accuracy of the protected area from the macroscopic morphology level.

[0070] For example, in an implementation of pre-coating protection for metal workpieces with complex geometries, the system triggers multi-dimensional verification logic: The boundary accuracy conditions are met (all deviations ≤ 0.1mm, no hidden dangers). The displacement sensor on the test bench detects a looseness of 0.02mm (<0.03mm) in the workpiece and cover, and the bench repeatability error is 0.015mm (≤0.02mm), which meets the bench positioning conditions. The image of the protected area captured by the vision module matches the shaded area of ​​the design drawing with a success rate of over 99.5%, meeting the visual recognition requirements.

[0071] Once all conditions are met, the system automatically outputs a "protection scheme confirmed" signal, triggering the bench electromagnetic lock to lock the workpiece and cover position; generates a protection confirmation report, recording information such as the maximum boundary deviation of 0.08mm, no hidden dangers during inspection, and confirmation time 20XX-XX-XX 14:35, and stores the report in the database for traceability; at the same time, it allows entry into the subsequent machining process, during which the workpiece and cover do not shift, and the protection status is stable.

[0072] By implementing the above method, the maximum boundary deviation of the protected area of ​​the metal workpiece is controlled within 0.08mm (≤ preset threshold 0.1mm), and the gap between the masking part and the workpiece is ≤0.05mm. There are no blind spots or looseness, which fully meets the protection requirements of subsequent machining for non-machined areas. This effectively avoids paint seeping into the gap between the masking part and the workpiece during the spraying process, forming "paint overflow", and prevents residual paint layers on the surface of the protected areas (such as precision connection holes, sealing surfaces, and marking areas), thereby ensuring the assembly accuracy of the subsequent workpiece. At the same time, precise path control prevents "overspraying" caused by path deviation of the spraying equipment, avoids paint incorrectly covering the functional structure of the protected area, and eliminates the need for subsequent manual scraping of residual paint layers. This not only reduces rework costs but also eliminates the risk of workpiece scratches. Furthermore, the blind-spot-free masking design ensures that all non-coated areas of the workpiece are precisely protected, avoiding paint adhesion caused by localized missed protection. This ensures the consistency of the workpiece's appearance and functional integrity, providing a foundation for uniform film formation and coating quality in subsequent coating areas. The final protection confirmation report contains complete data records that can be retrieved and reviewed at any time, facilitating subsequent quality traceability and process optimization. At the same time, the abnormal emergency mechanism (such as a brief failure of the vision module during the process, after which the system saves the data and resumes the process) ensures the continuity of operations, avoiding data loss or repetitive operations caused by unexpected interruptions, and significantly improving the robustness and efficiency of the overall production process.

[0073] Based on the same inventive concept, this application also provides a vision-scanning-based precision control system for sprayed protective areas, the precision control system comprising: The processing module is used to acquire the design boundary data of the area to be protected in the workpiece to be coated; The visual scanning module is used to simultaneously acquire the actual three-dimensional spatial data of the cover installed on the surface of the workpiece and the workpiece, and to map the design boundary data and the actual three-dimensional spatial data to the same physical coordinate system, thereby establishing the spatial relationship between the actual boundary and the design boundary of the workpiece and the cover. The path generation module is used to obtain the deviation value between the actual boundary data and the design boundary data of the covering component based on the spatial correlation. Determine whether the deviation value exceeds a first preset threshold, and determine the boundary reference data used for path generation based on the determination result; If the deviation exceeds the limit, the boundary of the covering element is corrected based on the deviation value, and the corrected boundary data is used as the boundary reference data. If it does not exceed the limit, the actual boundary data of the covering element will be used as the boundary reference data. Based on the boundary reference data, a protection boundary inspection path is generated; The verification module is used to detect the adhesion state between the cover and the workpiece surface and the boundary integrity of the cover itself based on the inspection path of the protection boundary, and obtain the verification result. The execution feedback module is used to perform multi-dimensional automatic verification based on the verification results. When all the verification conditions of the preset dimensions are met, a verification signal indicating that the protection scheme is qualified is output.

[0074] This application focuses on the various technical aspects involved in the part spraying process, including design drawing analysis, workpiece scanning, deviation detection, path generation, and spraying execution. Through the entire process of "drawing boundary extraction - 3D scanning positioning - deviation quantification calculation - compensation correction", the matching deviation between the masking part and the design shadow area is strictly controlled within the preset accuracy threshold, solving the masking offset problem caused by "design and physical object decoupling" in traditional positioning methods.

[0075] This application optimizes protection paths in multiple dimensions and controls the entire process precisely. The generated protection boundary inspection path not only meets the geometric accuracy requirements, but also adapts to the surface morphology of the workpiece and the characteristics of the bench operation. It solves the problems of "blind spots in boundary inspection, gaps in protection fit, and loose position" that are common in traditional protection methods. It achieves all-round reliable protection from design to execution and significantly improves the accuracy, stability and repeatability of spray protection.

[0076] In this specification, the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the descriptions of the embodiments described later are relatively simple, and relevant parts can be referred to the descriptions of the foregoing embodiments.

[0077] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for controlling the precision of a sprayed protective area based on vision scanning, characterized in that, include: Obtain the design boundary data of the protected area in the workpiece to be coated; Through three-dimensional vision scanning, the actual three-dimensional spatial data of the cover installed on the surface of the workpiece and the workpiece are acquired simultaneously, and the design boundary data and the actual three-dimensional spatial data are mapped to the same physical coordinate system to establish the spatial relationship between the actual boundary and the design boundary of the workpiece and the cover. Based on the spatial correlation, the deviation between the actual boundary data and the design boundary data of the covering component is obtained; Determine whether the deviation value exceeds a first preset threshold, and determine the boundary reference data used for path generation based on the determination result; If the deviation exceeds the limit, the boundary of the covering element is corrected based on the deviation value, and the corrected boundary data is used as the boundary reference data. If it does not exceed the limit, the actual boundary data of the covering element will be used as the boundary reference data. Based on the boundary reference data, a protection boundary inspection path is generated; Based on the inspection path of the protection boundary, the adhesion state between the cover and the workpiece surface and the boundary integrity of the cover itself are detected to obtain the verification result. Based on the verification results, multi-dimensional automatic verification is performed. When all preset verification conditions are met, a verification signal indicating that the protection scheme is qualified is output.

2. The method for controlling the precision of the sprayed protective area according to claim 1, characterized in that, Establishing the spatial association includes: A physical coordinate system is established with the positioning features on the stand that fixes the workpiece as the origin; Map the actual three-dimensional spatial data to the physical coordinate system; The design boundary data is transformed from the drawing coordinate system to the physical coordinate system through rigid transformation.

3. The method for controlling the precision of the sprayed protective area according to claim 1, characterized in that, The deviation between the actual boundary data and the design boundary data of the covering component is obtained through the following steps: Under the same physical coordinate system, the actual boundary data of the covering component is compared with the design boundary data point by point; Based on the Euclidean distance formula, the spatial distance between each point in the actual boundary data of the cover and the corresponding point in the design boundary data is calculated to obtain the deviation value of each corresponding boundary point.

4. The method for controlling the precision of the sprayed protective area according to claim 1, characterized in that, The step of correcting the boundary of the covering element based on the deviation value includes: With the goal of minimizing the deviation value, the least squares compensation algorithm is used to fit the spatial deviation of the actual boundary data of the cover relative to the design boundary data to obtain the corrected boundary data.

5. The method for controlling the precision of the sprayed protective area according to claim 1, characterized in that, The protection boundary inspection path must meet the following requirements: Completely covers the contact boundary between the cover and the workpiece surface; When there are multiple masking elements, the splicing boundaries between all masking elements must also be completely covered; The spacing between adjacent path points in the protection boundary inspection path is set according to a preset protection accuracy threshold.

6. The method for controlling the precision of the sprayed protective area according to claim 5, characterized in that, After generating the protection boundary inspection path, noise reduction processing is performed on the protection boundary inspection path, including: Based on the coordinates of the path points, the tangent angles of adjacent path points are obtained; The positions of the path points are adjusted according to the changes in the tangent angle to eliminate abrupt changes or intersections in the path.

7. The method for controlling the precision of the sprayed protective area according to claim 1, characterized in that, The detection of the adhesion state between the cover and the workpiece surface and the boundary integrity of the cover itself includes: The visual sensor moves along the inspection path of the protection boundary to collect image data or three-dimensional point cloud data of the interface area between the cover and the workpiece surface in real time. Based on the image or 3D point cloud data, the gap value between the actual boundary of the masking component and the workpiece surface is obtained; Determine whether the gap value at the verification location exceeds a preset bonding tolerance threshold. If it does, the verification location is identified as a bonding defect point, and the location information is recorded. Based on the image or 3D point cloud data, the real-time boundary data of the masking component at the current verification position is obtained; The real-time boundary data is compared with the boundary reference data to determine whether the boundary of the verification position is damaged, missing, warped, or the local offset exceeds the preset contour offset threshold. If so, the verification position is determined as an integrity defect point and the position information is recorded.

8. The method for controlling the precision of the sprayed protective area according to claim 7, characterized in that, Based on the test results, a verification report is generated; If no fitting defects or integrity defects are detected, a protection boundary verification report will be generated. If at least one defect is detected, a protection boundary verification anomaly report is generated; The protection boundary verification anomaly report includes at least: defect location information and correction suggestions.

9. The method for controlling the precision of the sprayed protective area according to claim 1, characterized in that, The confirmation conditions for the preset dimension include: Boundary accuracy conditions: Based on the verification results, it is confirmed that the deviation values ​​between the boundary reference data and the design boundary do not exceed the first preset threshold, and there are no unresolved protection vulnerabilities. The bench positioning conditions are as follows: the positioning looseness of the workpiece and the cover on the bench is less than the second preset threshold, and the repeatability error of the bench itself is less than the third preset threshold. The visual matching condition is based on an image similarity algorithm to obtain the similarity between the real-time image of the area to be protected on the workpiece and the corresponding area image in the design drawing, and to confirm that the similarity is not lower than a preset matching threshold.

10. A precision control system for sprayed protective areas based on vision scanning, characterized in that, The precision control system for the sprayed protection area includes: The processing module is used to acquire the design boundary data of the area to be protected in the workpiece to be coated; The visual scanning module is used to simultaneously acquire the actual three-dimensional spatial data of the cover installed on the surface of the workpiece and the workpiece, and to map the design boundary data and the actual three-dimensional spatial data to the same physical coordinate system, thereby establishing the spatial relationship between the actual boundary and the design boundary of the workpiece and the cover. The path generation module is used to obtain the deviation value between the actual boundary data and the design boundary data of the covering component based on the spatial correlation. Determine whether the deviation value exceeds a first preset threshold, and determine the boundary reference data used for path generation based on the determination result; If the deviation exceeds the limit, the boundary of the covering element is corrected based on the deviation value, and the corrected boundary data is used as the boundary reference data. If it does not exceed the limit, the actual boundary data of the covering element will be used as the boundary reference data. Based on the boundary reference data, a protection boundary inspection path is generated; The verification module is used to detect the adhesion state between the cover and the workpiece surface and the boundary integrity of the cover itself based on the inspection path of the protection boundary, and obtain the verification result. The execution feedback module is used to perform multi-dimensional automatic verification based on the verification results. When all the verification conditions of the preset dimensions are met, a verification signal indicating that the protection scheme is qualified is output.

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